It is frequently desirable to monitor or track the movement of a mass of air. For example, air mass movement is important in weather forecasting where it is often monitored by examining changes in ambient atmospheric pressure. Studies of the phenomenon of acid rain, industrial plant emissions or of chemical or biological weapon attacks also need physical verification of the expected movement of the air masses involved in order to ascertain whether various predictions or assumptions are valid.
Theoretical discussions of air mass movement can be found in the "Air Pollution Handbook", McGill et al. (McGraw-Hill Book Co., 1956) Section 4-54 at pp. 54-59; Sutton, "Atmospheric Turbulence" (John Wiley & Sons, 1949); and Sutton, "Micrometeorology" (McGraw-Hill Book Co., 1953).
One of the present means of monitoring the movement of an air mass has been by releasing fluorescent particles of zinc cadmium sulfide or zinc sulfide into the air and sometimes by the release of a radioactive particle. A sample of the air mass is collected downwind. The presence of the fluorescent particles or radioactive particles in the collected sample is thereafter determined using suitable equipment such as, for example, a fluorometer or a radioactive counter. However, cadmium is known to be toxic and therefore its use is undesirable. It is also undesirable to release sulfides into the atmosphere or to release radioactive materials into the atmosphere. Accordingly, a need exists for a safe and reliable method of tracing air mass movement.
It is accordingly the object of this invention to provide a method for the monitoring of the movement of an air mass without the release of toxic, radioactive or other undesirable material into the atmosphere. This and other objects of the invention will become apparent to those of ordinary skill in this art from the following detailed disclosure.